<SUBMISSION>
<ACCESSION-NUMBER>0001022079-04-000101
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>2
<PERIOD>20040504
<FILING-DATE>20040506
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>FLAHERTY JAMES F III
<CIK>0001201560
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-12215
<FILM-NUMBER>04785677
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>4675 MACARTHUR COURT
<CITY>NEWPORT BEACH
<STATE>CA
<ZIP>92660
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>C/O QUEST DIAGNOSTICS INC
<STREET2>ONE MALCOLM AVE
<CITY>TETERBORO
<STATE>NJ
<ZIP>07608
</MAIL-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>QUEST DIAGNOSTICS INC
<CIK>0001022079
<ASSIGNED-SIC>8071
<IRS-NUMBER>161387862
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>ONE MALCOLM AVE
<CITY>TETERBORO
<STATE>NJ
<ZIP>07608
<PHONE>2013935000
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>ONE MALCOLM AVE
<CITY>TETERBORO
<STATE>NJ
<ZIP>07601
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>CORNING CLINICAL LABORATORIES INC
<DATE-CHANGED>19960903
</FORMER-COMPANY>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-05-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001022079</issuerCik>
        <issuerName>QUEST DIAGNOSTICS INC</issuerName>
        <issuerTradingSymbol>DGX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001201560</rptOwnerCik>
            <rptOwnerName>FLAHERTY JAMES F III</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O QUEST DIAGNOSTICS INC</rptOwnerStreet1>
            <rptOwnerStreet2>ONE MALCOLM AVE</rptOwnerStreet2>
            <rptOwnerCity>TETERBORO</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07608</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Options (Right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>85.25</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-05-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2008-05-04</value>
            </exerciseDate>
            <expirationDate>
                <value>2014-05-04</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>10000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <ownerSignature>
        <signatureName>Sirisha Gummaregula, for James Flaherty III</signatureName>
        <signatureDate>2004-05-06</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>flahertypoa-41304.txt
<DESCRIPTION>POWER OF ATTORNEY
<TEXT>
POWER OF ATTORNEY


	Know all by these presents, that the undersigned
hereby constitutes and appoints each of Sirisha Gummaregula,
Michael E. Prevoznik, and Leo C. Farrenkopf, Jr., signing
singly, the undersigned's true and lawful attorney-in-
fact to:

(1)	execute for and on behalf of the undersigned,
in the undersigned's capacity as an executive officer
and/or director of Quest Diagnostics Incorporated
(the "Company"), Form ID Applications and Forms 3, 4
and 5 in accordance with Section 16(a) of the
Securities Exchange Act of 1934 and the rules thereunder;

(2)	do and perform any and all acts for and on behalf
of the undersigned which may be necessary or desirable to
complete and execute any such Form ID Application, Form 3,
4 or 5, complete and execute any amendment or amendments
thereto, and timely  file such form with the United States
Securities and Exchange Commission and any other authority;
and

(3)	take any other action of any type whatsoever in
connection with the foregoing which, in the opinion of
such attorney-in-fact, may be of benefit to, in the best
interest of, or legally required by, the undersigned, it
being understood that the documents executed by such
attorney-in-fact on behalf of the undersigned pursuant
to this Power of Attorney shall be in such form and shall
contain such terms and conditions as such attorney-in-fact
may approve in such attorney-in-fact's discretion.

	The undersigned hereby grants to each such
attorney-in-fact full power and authority to do and perform
all and every act and thing whatsoever requisite, necessary
and proper to be done in the exercise of any of the rights
and powers herein granted, as fully to all intents and purposes
as the undersigned might or could do if personally present, with
full power of substitution or revocation, hereby ratifying and
confirming all that such attorney-in-fact, or such attorney-
in-fact's substitute or substitutes, shall lawfully do or
cause to be done by virtue of this power of attorney and the
rights and powers herein granted.  The undersigned acknowledges
that the foregoing attorneys-in-fact, in serving in such capacity
at the request of the undersigned, are not assuming, nor is the
company assuming, any of the undersigned's responsibilities to
comply with Section 16 of the Securities Exchange Act of 1934.

	This Power of Attorney shall remain in full force and
effect until the undersigned is no longer required to file Forms
3, 4, and 5 with respect to the undersigned's holdings of and
transactions in securities issued by the Company, unless earlier
revoked by the undersigned in a signed writing delivered to the
foregoing attorneys-in-fact.

	IN WITNESS WHEREOF, the undersigned has caused this
Power of Attorney to be executed as of this 13th day of
April, 2004.

	/s/James F. Flaherty III
	Signature
	JAMES F. FLAHERTY III



STATE OF CALIFORNIA	)
	 		):  ss.
COUNTY OF LOS ANGELES 	)

	On this 13th day of April, 2004, before me, the
subscriber, personally appeared JAMES F. FLAHERTY III, to me
and known to me to be the same person described in and who
executed the foregoing instrument, and he duly acknowledged
to me that he executed the same.


	/s/Mary V. Wyatt
	Notary Public
	Comm.# 1333154
	Notary Public - California
	Orange County
	My Comm. Expires Dec. 3, 2005

</TEXT>
</DOCUMENT>
</SUBMISSION>
